Placental and Fetal Brain Volumes in Congenital Heart Disease Are Smallest Among Fetuses With Genetic Abnormalities.

To compare placental volumes between pregnancies with and without fetal CHD, including fetuses with CHD and genetic abnormalities, and to investigate the association between placental volume and regional fetal brain volumes. Pregnant women carrying a fetus with critical CHD with or without a genetic abnormality (CHD Genetic or CHD Isolated) or a fetus without CHD (Control) had placental and fetal brain volumes measured from MRI. Mixed effects linear regression models examined the associations between study group and placental and fetal brain volumes. Seventy-one pregnant women/fetuses underwent 124 MRIs. In multivariate analysis, placental volume was 33% smaller among CHD Genetic males, 15% smaller among CHD Isolated males, and 7% smaller among CHD Genetic females compared to Control males. Adjusting for placental volume and confounders, CHD Genetic had smaller total and regional brain volumes compared to Controls. Fetal cortex was not smaller at baseline, but the difference grew over gestation. Reduced brain volumes were present, but less pronounced, for CHD Isolated. Placental volume was independently associated with subcortical gray matter, total brain, and intracranial volumes. Impaired placental and fetal brain development are most prominent for CHD fetuses with genetic abnormalities.